scholarly journals Development and Types of Passive Samplers for Monitoring Atmospheric NO2 and NH3 Concentrations

2001 ◽  
Vol 1 ◽  
pp. 513-529 ◽  
Author(s):  
Y.S. Tang ◽  
J.N. Cape ◽  
M.A. Sutton
Keyword(s):  
Rural Areas ◽  
Sampling Rate ◽  
Reference Method ◽  
Diffusion Path ◽  
Ambient Air ◽  
Passive Samplers ◽  
Diffusion Resistance ◽  
Positive Bias ◽  
Diffusion Tubes ◽  
Term Monitoring

Numerous passive samplers based on the ‘Palmes-tube’ have been developed for ambient air monitoring. In each case, the diffusion path length and/or crosssectional area are modified to achieve the desired sampling rate. ‘Tube-type’ samplers are low sensitivity samplers suitable for long-term monitoring, whereas the ‘badge-type’ samplers have faster sampling rates suited to short-term monitoring. In the U.K., diffusion tubes are widely used for monitoring nitrogen dioxide (NO2) and ammonia (NH3). The open-ended diffusion tubes are prone to positive bias caused by incursion of wind eddies, leading to a shortening of the diffusion path. By using a porous membrane at the inlet, wind incursion is prevented, but an additional diffusion resistance is imposed and it is necessary to calibrate the tubes against a reference method to obtain an effective sampling rate. For NO2 sampling, positive bias also arises from the reaction of NO with O3 within the sampler. The interference from the chemical reaction is severe close to NO sources, with errors up to 30% for curbside locations when using the ‘tubetype’ sampler. In rural areas, where NO concentrations are small relative to NO2, these errors are small. In some implementations, there is also a negative bias over long sampling periods caused by the degradation of trapped NO2. The low sampling rates of diffusion tubes make them too uncertain for use at background NH3 concentrations (<1 μg NH3 m-3) where they significantly overestimate concentrations. Badge-type samplers such as the ‘Willems badge’ samplers permit accurate sampling at low ambient NH3 concentrations, but suffer from saturation at high concentrations and sensitivity to wind speed. A passive sampler optimised for monthly measurements of NH3 is reported here, together with its application in the U.K. National Ammonia Monitoring Network.

scholarly journals Development of a highly sensitive sampler for atmospheric monitoring of 8-H ambient ozone concentrations

2020 ◽  
Vol 25 (6) ◽  
pp. 938-945
Author(s):  
Gülnihal KARA
Keyword(s):  
Urban Areas ◽  
Sampling Rate ◽  
Composite Membranes ◽  
Ambient Air ◽  
Absorption Capacity ◽  
Passive Sampler ◽  
Passive Samplers ◽  
Winter Period ◽  
Highly Sensitive ◽  
Measurement Results

A new passive sampler reinforced with a composite membrane was developed to determine the 8-h ozone (O3) concentration in ambient air. The composite membrane's water absorption capacity and porosity values were found analyzing its surface morphology using Scanning Electron Microscopy (SEM).Ozone adsorption performance of this sampler was tested by a badge-type sampler and automated measurement results. The developed sampler gave results equivalent (R<sup>2</sup> = 0.85) to those of automated O3 monitors, and its experimental sampling rate was determined to be 55 cm<sup>3</sup>/min, approximately two times higher than the rate of the badge-type sampler. The detection limit obtained (5.3 μg/m<sup>3<.sup>, 8 h sampling) in the study was adequate for winter-period samplings where in the ozone concentration is low in urban and semi-urban areas. Multimedia sampling results revealed that the results of the developed passive sampler had a high repeatability (RSD < 20%). Passive samplers reinforced with composite membranes were tested by badge-type samplers performing simultaneous samplings in land conditions. Area sampling results indicated that badge-type samplers were not suitable for 8-h area samplings, but tube-type samplers could be used.

scholarly journals Comparison of PM10 washout on urban and rural areas

2017 ◽  
Vol 24 (3) ◽  
pp. 381-395 ◽  
Author(s):  
Tomasz Olszowski
Keyword(s):  
Rural Area ◽  
Rural Areas ◽  
Large Scale ◽  
Reference Method ◽  
Ambient Air ◽  
Constant Intensity ◽  
Continuous Precipitation ◽  
Concentration Changes ◽  
Urban And Rural Areas

Abstract This paper reports the results of research into the effectiveness of scavenging of PM10, resulting from the occurrence of solid and liquid hydrometeors. The measurement campaign was undertaken over 7 years and involved the registration of PM10 in areas which have different aerosanitary conditions (i.e. urban and undeveloped rural area). The analysis involved 426 observations taken at constant time intervals of 0.5 hour. The measurements of the concentration of PM10 were performed by means of a reference method accompanied by concurrent registration of basic meteorological parameters. It was indicated that in a urban location, the intensity of the local emission sources is a principal factor influencing the value of mass concentration changes and the effectiveness of the dust scavenging that accompanies a given type of precipitation. It was also noted that for the same intensity of precipitation, only the deposition of convective rainfall and long-term large-scale precipitation do not lead to statistically relevant differences in the value of mass concentrations of dust for both areas. It was indicated that during solid and liquid frontal precipitation of light intensity (< 0.5 mm·h−1), the effectiveness of PM10 removing is less in rural area. It was statistically proven that continuous precipitation of constant intensity and duration exceeding 2 hours has a similar effect of purifying the ambient air in both locations. The study revealed that short-term solid precipitation provides better characteristics of scavenging of PM10 compared with classic rainfall

scholarly journals Ambient Air Quality Measurement with Low-Cost Optical and Electrochemical Sensors: An Evaluation of Continuous Year-Long Operation

Environments ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 114
Author(s):  
Jiří Bílek ◽  
Ondřej Bílek ◽  
Petr Maršolek ◽  
Pavel Buček
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Sensor Network ◽  
Electrochemical Sensors ◽  
Reference Method ◽  
Ambient Air ◽  
Sensor Data ◽  
Dust Particles ◽  
Concentration Changes ◽  
The Impact

Sensor technology is attractive to the public due to its availability and ease of use. However, its usage raises numerous questions. The general trustworthiness of sensor data is widely discussed, especially with regard to accuracy, precision, and long-term signal stability. The VSB-Technical University of Ostrava has operated an air quality sensor network for more than two years, and its large sets of valid results can help in understanding the limitations of sensory measurement. Monitoring is focused on the concentrations of dust particles, NO2, and ozone to verify the impact of newly planted greenery on the reduction in air pollution. The sensor network currently covers an open field on the outskirts of Ostrava, between Liberty Ironworks and the nearby ISKO1650 monitoring station, where some of the worst air pollution levels in the Czech Republic are regularly measured. In the future, trees should be allowed to grow over the sensors, enabling assessment of the green barrier effect on air pollution. As expected, the service life of the sensors varies from 1 to 3 years; therefore, checks are necessary both prior to the measurement and regularly during operation, verifying output stability and overall performance. Results of the PMx sensory measurements correlated well with the reference method. Concentration values measured by NO2 sensors correlated poorly with the reference method, although timeline plots of concentration changes were in accordance. We suggest that a comparison of timelines should be used for air quality evaluations, rather than particular values. The results showed that the sensor measurements are not yet suitable to replace the reference methods, and dense sensor networks proved useful and robust tools for indicative air quality measurements (AQM).

scholarly journals THE INFLUENCE OF ABSORBENT SOLUTION ON THE EFFECTIVENESS OF PASSIVE DIFFUSIVE SAMPLERS

2010 ◽  
Vol 2 (5) ◽  
pp. 103-108 ◽  
Author(s):  
Vaida Šerevičienė ◽  
Vaida Valuntaitė ◽  
Dainius Paliulis
Keyword(s):  
Aqueous Solutions ◽  
Ambient Air ◽  
Gas Diffusion ◽  
Passive Samplers ◽  
Oxides Of Nitrogen ◽  
The European Union ◽  
Absorption Mechanism ◽  
True Meaning ◽  
Almost All ◽  
Absorbent Solution

The method of applying passive diffusive samplers for research on air quality is simple, easy enough and requires no electricity. The operating principle of almost all passive samplers is based on chemical reactions taking place on absorbent (impregnated filter or grid). The pollutant absorption mechanism is based on passive diffusion through the gas diffusion layer to absorbent. The diffusion process can be explained by first Fick’s law described as a free movement of gases from the ambient air to a passive sampler. This movement depends on pollutant gradient. The aim of this paper is to analyse the influence of an impregnating solution on the efficiency of diffusive samplers. The object of the study covers the triethanolamine (TEA) aqueous solutions of 5%, 10%, 20%, 30% and 50%. The results obtained showed that 30% and 50% aqueous solution gave 68% and 89% relative error making the true meaning of the oxides of nitrogen analyzer testimony. Data on the passive samplers impregnated with TEA aqueous solutions having concentrations of 5%, 10% and 20% are within definite 25% uncertainty established by the European Union Directives.

scholarly journals δ 13 C methane source signatures from tropical wetland and rice field emissions

2021 ◽  
Vol 380 (2215) ◽  
Author(s):  
James L. France ◽  
Rebecca E. Fisher ◽  
David Lowry ◽  
Grant Allen ◽  
Marcos F. Andrade ◽  
...  
Keyword(s):  
Rice Field ◽  
Ambient Air ◽  
Atmospheric Methane ◽  
Isotopic Signatures ◽  
Methane Budget ◽  
Significant Seasonal Variation ◽  
Methane Source ◽  
Wetland Extent ◽  
Term Monitoring

The atmospheric methane (CH 4 ) burden is rising sharply, but the causes are still not well understood. One factor of uncertainty is the importance of tropical CH 4 emissions into the global mix. Isotopic signatures of major sources remain poorly constrained, despite their usefulness in constraining the global methane budget. Here, a collection of new δ 13 C CH 4 signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. Long-term monitoring of δ 13 C CH 4 in ambient air has been conducted at the Chacaltaya observatory, Bolivia and Southern Botswana. Both long-term records are dominated by biogenic CH 4 sources, with isotopic signatures expected from wetland sources. From the longer-term Bolivian record, a seasonal isotopic shift is observed corresponding to wetland extent suggesting that there is input of relatively isotopically light CH 4 to the atmosphere during periods of reduced wetland extent. This new data expands the geographical extent and range of measurements of tropical wetland and rice δ 13 C CH 4 sources and hints at significant seasonal variation in tropical wetland δ 13 C CH 4 signatures which may be important to capture in future global and regional models. This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’.

scholarly journals Uncertainty of PM10 concentration measurement on the example of an optical measuring device

2018 ◽  
Vol 57 ◽  
pp. 02008 ◽  
Author(s):  
Tomasz Owczarek ◽  
Mariusz Rogulski
Keyword(s):  
Regression Models ◽  
Test Procedure ◽  
Reference Method ◽  
Ambient Air ◽  
Alternative Methods ◽  
Linear Regression Models ◽  
Measuring Device ◽  
Incomplete Knowledge ◽  
Uncertainty Of Measurements ◽  
Definition Of

The interest in the natural environment, in particular the ambient air, has been growing. For this reason, growing interest in measuring of concentration of pollutants in the air. To the reduction of costs and time of obtained results, increasingly are used non-reference, alternative methods and devices. However, it is necessary to ensure equivalence of results obtained by alternative methods with the results of the reference method. One of the equivalence issues is the assessment of the measurements uncertainty of the alternative method in relation to the reference method. This uncertainty is understood as the probability of obtaining a measurement result which differs from the real (reference) result by a predetermined value. Uncertainty can be caused by many reasons: imperfect implementation of the definition of the measurand, incomplete knowledge of the influence of external factors, heterogeneity of the analyzed phenomenon, errors of the measuring device and others. The paper presents methods for testing the uncertainty of measurements used in the study of equivalence and also proposed extending the test procedure with equivalence models, different from the linear regression models.

scholarly journals Comparison of diffusion tube–measured nitrogen dioxide concentrations at child and adult breathing heights: who are we monitoring for?

2020 ◽  
Vol 14 (1) ◽  
pp. 27-36
Author(s):  
Alex Rowell ◽  
Michael E. Terry ◽  
Michael E. Deary
Keyword(s):  
Nitrogen Dioxide ◽  
City Council ◽  
Passive Samplers ◽  
Urban Setting ◽  
Concentration Gradients ◽  
Diffusion Tubes ◽  
Significant Difference ◽  
Building Facades ◽  
Sampling Height ◽  
Newcastle Upon Tyne

AbstractMany towns and cities use passive samplers (diffusion tubes) to monitor nitrogen dioxide (NO2) concentration. However, literature studies have shown large horizontal and vertical concentration gradients for diffusion tubes placed over short distances, raising concerns over the representativeness of monitoring locations. This study examines variations in NO2 concentrations with height at two roadside locations along a busy urban road in Newcastle upon Tyne (UK) over an 8-month period. NO2 concentrations were passively monitored at building facades (approximately 7.0 m from the roadside) at heights of 0.7 m, 1.7 m and 2.7 m to replicate child breathing height in prams and buggies, adult breathing height and the Newcastle City Council sampling height (for 2017), respectively. Paired t tests indicated that NO2 concentrations were significantly lower at 2.7 m (4.7% lower, n = 16, p = 0.001) and 1.7 m (7.1% lower, n = 14, p = 0.007) compared with those at 0.7 m. There was no statistically significant difference between NO2 concentrations measured at 2.7 m and 1.7 m, indicating that UK local authority practice of placing diffusion tubes at higher than adult breathing height does not result in underreporting of NO2 concentrations for regulatory purposes. The results have clear public health implications as they provide evidence that young children, in an urban setting and close to busy roadways, may be exposed to higher NO2 concentrations compared with adults in the same location. We have shown that such differences might not be adequately reflected in the monitoring data from municipal authorities.

Monitoring of tropospheric ozone in the ambient air with passive samplers

2011 ◽  
Vol 99 (2) ◽  
pp. 383-387 ◽  
Author(s):  
Daniellys Alejo ◽  
Mayra C. Morales ◽  
Vladimir Nuñez ◽  
László Bencs ◽  
René Van Grieken ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Ambient Air ◽  
Passive Samplers

scholarly journals Quantification Method for Electrolytic Sensors in Long-Term Monitoring of Ambient Air Quality

Sensors ◽  
2015 ◽  
Vol 15 (10) ◽  
pp. 27283-27302 ◽  
Author(s):  
Nicholas Masson ◽  
Ricardo Piedrahita ◽  
Michael Hannigan
Keyword(s):  
Air Quality ◽  
Ambient Air ◽  
Ambient Air Quality ◽  
Quantification Method ◽  
Long Term Monitoring ◽  
Term Monitoring

scholarly journals Instrumental measurement of odour nuisance in city agglomeration using electronic nose

2018 ◽  
Vol 28 ◽  
pp. 01012 ◽  
Author(s):  
Bartosz Szulczyński ◽  
Tomasz Dymerski ◽  
Jacek Gębicki ◽  
Jacek Namieśnik
Keyword(s):  
Electronic Nose ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Reference Method ◽  
Monitoring Network ◽  
Ambient Air ◽  
Processing Plant ◽  
Production Plant ◽  
Oil Processing

The paper describes an operation principle of odour nuisance monitoring network in a city agglomeration. Moreover, it presents the results of investigation on ambient air quality with respect to odour obtained during six-month period. The investigation was carried out using a network comprised of six prototypes of electronic nose and Nasal Ranger field olfactometers employed as a reference method. The monitoring network consisted of two measurement stations localized in a vicinity of crude oil processing plant and four stations localized near the main emitters of volatile odorous compounds such as sewage treatment plant, municipal landfill, phosphatic fertilizer production plant. The electronic nose prototype was equipped with a set of six semiconductor sensors by FIGARO Co. and one PID-type sensor. The field olfactometers were utilized for determination of mean concentration of odorants and for calibration of the electronic nose prototypes in order to provide their proper operation. Mean monthly values of odour concentration depended on the site of measurement and on meteorological parameters. They were within 0 – 6.0 ou/m3 range. Performed investigations revealed the possibility of electronic nose instrument application as a tool for monitoring of odour nuisance.

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